Context: Planetary Nebulae (PNe) display complex radial surface brightness profiles whose understanding is crucial for a correct interpretation of their formation and evolution. In particular, the intermediate shells commonly observed around the bright rims of PNe contain important information for the discussion of the mass loss rate at the end of

Sources responsible for volcanic unrest produce characteristic surface deformation. Given a sufficient number of distributed observation points, inversion is the preferred procedure for retrieving the source parameters of location and volume or pressure change. Most often the solutions have been for point sources embedded in a homogeneous half

We present reliable measurements of the metallicity distribution function (MDF) at different points along the tidal stream of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy, based on high-resolution, echelle spectroscopy of candidate M giant members of the Sgr system. The Sgr MDF is found to evolve significantly from a median [Fe/H]~-0.4 in

We present Keck/LRIS optical spectroscopy of 35 z>=1.4 luminous IR galaxies in the Spitzer Wide-area Infra-Red Extragalactic survey (SWIRE) northern fields (Lockman Hole, ELAIS-N1, ELAIS-N2). The primary targets belong to the "IR-peak" class of galaxies, having the 1.6{mu}m (restframe) stellar feature detected in the IRAC Spitzer channels. The

We report the X-ray detection of Nova Vul 2007 (S. Nakano, IAUC 8861) with the Swift X-ray Telescope in a 6.7ks observation obtained on 2007 October 18 at UT 01:05. The XRT spectrum contains 192 X-ray photons and is largely consistent with a thermal plasma model with temperature kT=0.2 +0.4/-0.07 keV and absorbing column NH=(8 +2/-3)e21 cm^-2. A

The main goal of this work is the analysis of new approaches in order to study the properties of astronomical sites. The objective is to calibrate the atmospheric extinction provided by in situ techniques through remote sensing data retrieved from satellite-platforms. We have explored the usefulness of data provided by different spectrographs